Pimax Experience does some things for you behind the scenes such as ensuring the steamVR config files are configured correctly for Pimax headsets
GPUspeed values , max resoulution.
Other than that It supports viveport and stuff.
You dont really need it to use the Pimax though. For doing things like enabling Parallel Projections mode PiTool is all you need.
If theres one thing you should pay attention to with Pimax headsets its the Parallel Projections. Ideally you should not have to turn that on , because it incurs a 30% performance hit.
Some games require it or weird things happen.
Its only fixable in games by developers such as yourself.
I can’t remember, but I remember not being able to play GTA 5 real mod on the Largest FOV without the view being completely out of whack.